Ok, I had a chance to get some numbers off of the tranny and rear axle tube of my 1970 elky SS 396. Here they are:

Trans-

Pass side tag riveted on-

Yellow tag

Code no. 72 D (in yellow letters) 406 (stamped in tag)
Ser # 72-CD-11291

Driver side on flat area above where trans pan is-

stamped numbers 12B602 (602 very light and hard to read)

Rear axle stamping-

CCW 0220B2

If anyone has any info on what this decodes down to, I would much appreciate an answer as I am trying to document this car as a true SS since I have not found the original build sheet yet.

As always, all help is ever so grately appreciated.

Thanks,

Hi Brian, looks like your tranny is from a 1972, I'll check on that rear axle code when I get home today.

The stamped numbers of 12B602 decode as
1 = Chevrolet
2 = 1972
B = Balitmore Assembly plant
602 = this is the sequential production number of the original vehicle this tranny was installed in. It should have three more numbers (i.e. 602XXX)

I'm not sure what the other numbers from the tranny mean without looking at my books but I'll look when I get home and get back to you.

Hi, CCW would be for a 3.31:1 non posi traction rear axle. I don't know about any 1970 TH400's for sale, I would keep an eye in Hemmings, you never know whats going to show up there.

It seems that either the dealership put a posi unit in or someone else did but it is very plausible that the dealership put it in because when we got the car, there was a GM tow bar / towing package installed on it.

Its very weird that we have a numbers matching motor, a numbers matching rear axle, and eveything is original down to the date coded tower top hose clamps. With all of this being original, why would the trans have to be replaced with only 44,000 miles on it???? :? 8O